For hydraulic oil: I use John Deere oil and filters.
For motor oil: I choose full synthetic, name brand oil of overlapping required viscosity, with name brand filters.
Oil is cheap and equipment is not! Synthetic is the superior lubricant.
I use AMSOIL 4-STORKE SYNTHETIC !!!
Congrats on the Z920M, but there are a few morons on this site that are ignorant about JD, just preparing and warning you.
Anyway I use
JD Hydraulic fluid
Castrol Motor Oil with Kawasaki Oil Filter.
I know I've posted my opinion that JD's are over-priced...but hope you don't include me in those "few morons":0)
But your participation on the forums is very beneficial for everyone(despite the difference in your opinions that shughes717 or user Dsepe share). Your knowledge & experience is very helpful to other JD owners. I vote that we all put aside any differences in opinion regarding recommendations of brands for users seeking to purchase a ZTR......and try to assist others if we can. I think if another user agrees with your advice and demos a JD as he seeks to purchase a new ZTR that's great. The more ZTR's they look at the easier it will be to find what's right for them.
Just purchased a Z920M zero turn mower from John Deere. Any of you folks have this mower and if so what type of oil do you use. I figure that John Deere oil would be the most expensive.